The use of GeoGebra to construct Tales' Theorem

report of an experience in the 9th grade of elementary school

Abstract

This experience report deals with the application of the work developed in the subject of Digital Technologies in Mathematics Education, in the 1st year of the Mathematics Degree course at UNESPAR - Paranavaí campus, with the aim of retaking the content of Thales' Theorem using GeoGebra software. The activity was implemented with 32 students enrolled in the 9th grade of a public school in the city of Paranavaí. Initially, we asked questions about Thales' Theorem in order to construct a mental map on the board based on the students' prior knowledge. Then we divided the class into eight groups of four people each, to demonstrate the step-by-step construction of Tales' Theorem on GeoGebra software on multimedia television, with the support of the (future) teachers. We gave the students the commands to construct Thales' Theorem autonomously in the software, so that they had the opportunity to explore and handle GeoGebra. We noticed that some students had difficulty following the commands to arrive at an approximate construction of what was required in the proposed activity. However, another group of students managed to achieve what was required more easily. As first-year students on the Mathematics degree course, we can say that the experience gained from developing this activity has given us another look at the classroom and allowed us to understand the differences of each student.